What You Don't Know by Exposé first appeared on the Israeli foreign-music chart on 16 Jul 1989, entering at #16. It peaked at #8 on 30 Jul 1989. In total it spent 5 weeks on the chart, last charting on 13 Aug 1989.
| Wk | Date | Pos |
|---|---|---|
| 1 | 16 Jul 1989 | 16 |
| 2 | 23 Jul 1989 | 13 |
| 3 | 30 Jul 1989 | 8 |
| 4 | 6 Aug 1989 | 12 |
| 5 | 13 Aug 1989 | 22 |